The present invention concerns an improved process for manufacturing certain cyano-substituted sulfilimines.
Cyano-substituted sulfilimines are useful intermediates for the preparation of certain new insecticidal sulfoximines; see, for example, U.S. Pat. Nos. 7,678,920 B2 and 7,687,634 B2. U.S. Pat. No. 7,868,027 B2 describes the manufacture of substituted sulfilimines by the reaction of the corresponding sulfide with cyanamide and hypochlorite solution in a suitable organic solvent. While the hypochlorite process of U.S. Pat. No. 7,868,027 B2 is preferable to the iodobenzene diacetate process described in U.S. Pat. Nos. 7,678,920 B2 and 7,687,634 B2, it is plagued by significant levels of byproducts formed by competing reactions of the sulfide starting materials and the sulfilimine products.
Therefore, there is the need for inventions that are useful to produce the substituted sulfilimines efficiently and in higher yields.